[TriEmbed] Pi Zero W -- Touch Display Troubleshooting

[Ron Craig]

 Hi, gang.

I bought this display
<https://www.amazon.com/dp/B07L6WT77H?psc=1&ref=ppx_yo2ov_dt_b_product_details>
from Amazon. It states it works with the Pi Zero, but I cannot get Touch to
work on that. Touch works fine on a Pi 4B, but not the Zero.
Any hints?

I have made my own cables where needed, but Touchscreen still does not
work.  I am including my wiring setup below.  Am I missing something?  The
arrow on the OS screen moves the *first *time I touch the screen, but will
not move after that.  I think it is a software issue?  Are there drivers
needed for the Zero?











*pi at hamclock:~ $ cat /etc/os-releasePRETTY_NAME="Raspbian GNU/Linux 10
(buster)"NAME="Raspbian GNU/Linux"VERSION_ID="10"VERSION="10
(buster)"VERSION_CODENAME=busterID=raspbianID_LIKE=debianHOME_URL="http://www.raspbian.org/
<http://www.raspbian.org/>"SUPPORT_URL="http://www.raspbian.org/RaspbianForums
<http://www.raspbian.org/RaspbianForums>"BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs
<http://www.raspbian.org/RaspbianBugs>"*

*pi at hamclock:~ $ uname -aLinux hamclock 5.10.103+ #1529 Tue Mar 8 12:19:18
GMT 2022 armv6l GNU/Linux*


In the picture:
1: Power Block (5V 3.5A) to MICRO USB power connector on the Zero W.  No
under voltage warnings. All looks good.
2: DIY 4-wire cable from JST to MICRO USB connector on the Zero W.
Substitute for the 5V+Touch connector on the side.
3: Supplied FPC to MINI HDMI connector on the Zero.  Reaches fine once I
moved the Zero to another location (was too short if the Zero was installed
where suggested).

[image: Zero Connections small.png]
I've put Kapton tape on the back of the Zero W to prevent any electrical
shorts with the unused mounting post.

On bootup to 32-bit Raspberry OS, the desktop appears properly and the
picture looks great.  I can touch the screen EXACTLY ONE TIME, and the
arrow cursor will move to where I touched the screen.  It never moves after
that.

The application I use does not require a keyboard if I can use a
touchscreen. Without touch, I need a bluetooth mouse, which I would rather
not use. There are less expensive non-touch screens I think I could use if
touch will not work.

Any help is greatly appreciated. I've already printed a nice case and
swinging mounting arm for this display, so I would love to keep it and use
it if I can get touch to work.

Note that I've also tried power through the 5V IN connector, but the
behavior is exactly the same.

Generally, are there any gotchas with Touch and the Zero or Raspberry OS in
general I could try?

Best,
-- 
Ron Craig   KO4RON
J'ai bonne espérance!
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